How 3D printed forms make impossible architecture possible

Great turning points in architecture begin in unexpected ways. A new and inexpensive production process to transform iron into steel made possible the rise of skyscrapers in the 20th century. When computer-aided design (CAD) replaced the work of manual drafting, it paved the way for the precisely mapped curves of the sculptural buildings by Zaha Hadid and Frank Gehry. 

In the last decade, a new technology has opened up new possibilities: 3D printing. Also called additive manufacturing, 3D printing involves adding materials in precise layers to realize an object drawn from a digital file. 

After years of using it in their offices to print models, architects are now deploying 3D printing to create building elements and even whole structures. This permits them to reduce material waste, cut costs and development times, experiment with new materials, and create previously unseen architectural aesthetics. 

“3D printing can have a game-changing impact when it is used to connect different materials and construction systems, or when tooling and molding are prohibitively expensive or limiting,” says Tristan Morgan, computational design and automation lead at engineering company Aurecon.

For example, the Striatus Bridge, built in Venice in 2021 by Zaha Hadid Architects (ZHA) in their signature flowing style, demonstrated a responsible way to design with the construction industry’s most used and also most emissions-generating material: concrete. The bridge is constructed from fifty-three 3D-printed, uniquely shaped hollow blocks that would otherwise have required individual formwork (or molds), significantly cutting down on both the concrete needed and typical formwork materials of timber, metal, or plastic. 

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Without the constraints of having to remove objects from a mold (as in formative manufacturing) or having to carve out material (as in subtractive manufacturing), it is possible to create shapes that would have been impossible before, or, where they were possible, would have been prohibitively time-consuming and costly. 

“3D printing lets us create more efficient structures using nonstandard geometries, especially when it comes to printing complex junctions and joints on demand,” says Morgan. 

New shapes and complex forms 

The elaborate forms allowed by 3D printing mean architects can push the boundaries of what is possible. “Complexity is very interesting for architects because it means great design freedom,” says Andrei Jipa, an architect and researcher in ETH Zurich’s Digital Building Technologies (DBT) group, which carries out some of the most pioneering work in architectural 3D printing. “With 3D printing, we have a design vocabulary that is unrivaled by other fabrication processes.” 

DBT created a series of nine 9-foot-tall columns called Concrete Choreography that show the intricacy achievable through 3D printing. Each individually designed column has a unique fluid appearance, combining furrows, ridges, and hollows. The details are so finely designed that in places the concrete layers are just five millimeters thick. DBT also collaborated with other groups at ETH on the HighRes Concrete Slab ceiling made from 3D-printed molds and standard poured concrete. The molds allowed the team to create a ceiling with dramatic, flowing contours that would have taken a lot of time, money, and extra material to produce by other methods. 

The ceiling is installed in the NEST HiLo Unit in Dübendorf, a testing ground for futuristic construction techniques. The slab integrates a network of embedded heating and cooling water pipes that inform the organic contours, making it a highly efficient, thermally active panel due to the thinness of the concrete structure. The active ventilation is supplied by four 3D-printed air ducts incorporated directly into the structure. 

According to Jipa, another benefit of working with 3D-printed molds and a conventional concreting process is that it meets existing building codes. “This makes it available and ready,” he says. “We can use it now. There’s no further research that needs to go into developing new types of reinforcement, getting it approved for building standards, and so on.” 

South Korean firm HS Hi-Tech is another group using 3D printing, in this case to help build atypical facades and structures by making the complex joints and junctions that support them. For example, their Blobee pavilion, made to be installed in public areas to create a private space, has a construction combining plastic joints with glass panels into an angular dome. Each adaptive joint had to meet specific requirements to connect beams at different planes. HS Hi-Tech designed and produced these bespoke parts using HP Multi Jet Fusion 3D printing technology, which mixes powder and a binder to create a plastic polymer. 

“HP Multi Jet Fusion 3D printing technology has accelerated almost every process in our company,” said Seung Gyu Yu, head officer of the construction 3D printing laboratory at HS Hi-Tech when the Blobee was unveiled. “It allows engineers to maximize their freedom of design, and development can be very agile and helps to cost-effectively produce large quantities of customized products.” 

The company also partnered with the DBT group to build a pavilion made from one of the world’s most sustainable materials, bamboo, and which weighs less than 500 pounds. To fix the rods together into the sprawling, triple-cantilevered shape the designers imagined, they 3D printed 380 different joints customized to their location in the structure. Using commercial technology not only made the process quick and cost-effective, it also guaranteed that the pavilion can be replicated anywhere in the world by makers using locally grown bamboo, minimizing emissions from transport. 

Building with the unexpected 

Other architects are using the advent of 3D printing to explore construction with unusual materials, such as metal, sand, and even “living” materials like mycelium or seed-impregnated soil.

The MX3D Bridge in Amsterdam is one of the world’s most famous 3D-printed architectural projects, and the first to focus on metal. Designed by Joris Laarman and built by his robotics company from nearly five tons of pure stainless steel, it was made to demonstrate that 3D printing could work on a large scale by using robotic arms and an additive arc welding process. While there has been limited interest in using stainless steel at this scale due to its high embodied carbon, the bridge achieves a truly futuristic look, with sinuous balustrades and a delicate, lattice-like patterning that gives the impression of muscle moving under mesh. 

Other architects are pursuing more blue-sky ideas. London-based Blast Studio 3D prints structures from a biomaterial created by combining urban waste like pulped coffee cups and living bio organisms like mycelium, the branching root-like part of mushrooms. Mycelium has the ability to strengthen structures as it grows, giving it great potential as an all-natural architectural material. Using a custom printer with a cold extruder so as not to kill the organisms, the studio prints items like the six-foot-tall Tree Column, whose trunk-like structure supports the growth of mushrooms that can be eaten or house other life. Blast Studio cofounder Paola Garnousset imagines a structure like this being used for facades, pavilions, or kiosks that would sit within the cityscape to promote urban biodiversity. 

“We’re thinking a lot about the idea of an architecture that would be made for all living organisms,” says Garnousset. “With 3D printing you can design a piece that works both at the scale of the centimeter and have very small interstices into which insects can create their nest, and work on a bigger scale for humans.” 

Architecture made more sustainable 

There are several ways 3D printing can lessen the environmental impact of architecture: It eliminates the material wasted on molds that are used once, then destroyed; it allows parts to be replaced on demand; and it can reduce emissions from transport, as fewer trucks need to be sent to construction sites. But material reduction via optimization is where the biggest gains stand to be made. 

With 3D printing, designers are able to use the minimal amount of material necessary to make a structure sturdy, often through strategically placed branches and hollows. This is why computationally designed forms so often recall the shapes of tree trunks, leaves, shells, or insect nests — in nature, structures have perfectly adapted and optimized to their environment over millions of years, and architects and engineers are emulating this via biomimicry. 

The potential for a beneficial environmental impact is highest in the case of concrete. This single material notoriously causes around 8% of total global carbon dioxide emissions. Reducing how much is used could help the world in reaching carbon neutrality. In particular, building foundations are where concrete can’t be replaced by a lower-impact materials, as they need to be extremely rigid and strong to prevent a structure from sinking into the ground. Companies are using 3D printing to produce concrete pad foundations, such as the one made by Hyperion Robotics in Finland. Instead of a typical square or rectangular shape, it’s printed with support struts that almost resemble tree roots, and it uses only one-quarter of the concrete found in traditional foundations. 

The attractions of 3D printing are clear: material efficiency, lower costs, fast turnarounds, all while incorporating more varied and idiosyncratic aesthetics. Just as our urban structures were transformed by the development of cheap industrial steel, it could be that a disruption as large as the skyscraper lies ahead of us. 

“I suspect the true impact of 3D printing will not be doing the same things faster or with less labor, but in seeing more customized living within increasingly standardized buildings,” says Morgan. “It’s something that is able to be quickly deployed, yet flexible enough to be personalized, and adaptable to a complex and continually changing world.” 

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